氮肥减量后移对喷灌玉米产量和水氮利用效率的影响

【目的】优化井灌区田间水肥管理。【方法】试验于2018年6—9月在河南省许昌灌溉试验站进行,以当地主栽玉米品种登海3737(P1)和豫单9953(P2)为试验材料,设置3种施肥调控方式,分别为当地传统施肥模式CK(N、P2O5、K2O施量分别为315、75、75 kg/hm^2,全部基施),优化模式F1(N、P2O5、K2O施量分别为225、75、75kg/hm^2,40%三叶期和60%拔节期追肥),优化模式F2(N、P2O5、K2O施量分别为225、75、75kg/hm^2,30%三叶期、30%拔节期和40%大喇叭口期追肥),研究了喷灌水肥一体化下氮肥减量后移对不同品种夏玉米生长发育、产量和水分利用效率的影响。【结果】增加施肥频次和施肥时间后移可提高玉米叶面积系数(LAI)和延缓叶片衰老,增加玉米干物质累积量以及最大生长速率。喷灌水肥一体化(F1、F2处理均值)较传统施肥籽粒产量提高7.8%,耗水量降低11.9%,水分利用效率(WUE)提高22.2%,籽粒氮肥偏生产力(PFPY)提高51.1%,生物量氮肥偏生产力提高49.2%。登海3737干物质累积、最大生长速率、WUE和PFPY的均值较豫单9953分别增加2.8%、7.7%、8.5%和8.6%,最大生长速率出现的时间没有差异。豫单9953干物质积累快增期持续时间比登海3737增加5.3 d。不同品种之间产量和构成要素差异极显著。登海3737平均产量为11 319 kg/hm^2,较豫单9953增产8.4%,其中穗长、百粒质量对产量贡献较大,分别提高22.5%和18.2%。【结论】本研究中,F2处理为最佳施肥模式,即N、P2O5、K2O施量分别为225、75、75 kg/hm^2,施肥配比为30%三叶期、30%拔节期、40%大喇叭口期。

Impacts of Reducing and Delaying Nitrogen Application on Yield and Water and Nitrogen Use Efficiency of Summer Maize under Sprinkler Fertigation

【Objective】Optimizing irrigation and fertilization is essential to sustain crop production without compromising the environment.The objective of this paper is to experimentally study how reductions in fertilizer application affect yield and water and nitrogen use efficiency of maize in well-irrigation regions.【Method】The field experiment was conducted from June to September in 2018 at the Xuchang Irrigation Experiment Station in Henan province;two maize varieties,P1:cv.DH 3737 and P2:cv.YD9953,were used as model plant.We compared three fertilizations in which phosphorus and potassium applications were the same:75 kg/hm^2 of P2O5 and 75 kg/hm^2 of K2O were applied as base fertilization.The treatments differed only in their nitrogen applications:315 kg/hm^2 of N was applied as base fertilizer(CK),40%of 225 kg/hm^2 of N was applied at the 3-leaf stage with the remaining applied at the jointing stage(F1),30%of 225 kg/hm^2 was each applied at the 3-leaf stage and the jointing stage respectively,with the remaining applied at the bell-mouthed stage.The plants were watered and fertilized with sprinkler fertigation.In each treatment,we measured plant growth,grain yield,water and nitrogen use efficiency.【Result】Increasing N application frequency and delaying N topdressing improved leaf area index(LAI)and reduced leaf senescence,thereby boosting dry matter accumulation and plant growth rate.Compared to traditional fertilization,sprinkler fertigation improved grain yield,water use efficiency(WUE),partial fertilizer productivity(PFPY)for yield,and partial fertilizer productivity for biomass(PFPB)by 7.8%,22.2%,51.1%and 49.2%,respectively.In contrast,fertigation reduced crop water consumption by 11.9%.DH3737 increased dry matter accumulation,maximum growth rate,WUE and PFPY by 2.8%,7.7%,8.5%and 8.6%,respectively,compared to YD9953,despite the time period through which their growth rate maximized was approximately the same.The period of rapid increase in dry matter for YD9953 was 5.3d longer than that for DH3737.The grain yield of DH3737 was 11319 kg/hm^2,8.4%higher than that of YD9953,due to the 22.5%and 18.2%increase in ear length and 100-kernel respectively.【Conclusion】The optimal fertilization was to apply 75 kg/hm^2 of P2O5 and 75 kg/hm^2 of K2O as base fertilizers,with 30%of 225 kg/hm^2 applied each at the 3-leaf stage and the jointing stage,respectively,and the remaining applied at the bell-mouthed stage.